Fecal Akkermansia muciniphila Is Associated with Body Composition and Microbiota Diversity in Overweight and Obese Women with Breast Cancer Participating in a Presurgical Weight Loss Trial.

BACKGROUND

Akkermansia muciniphila (AM) is a gram-negative, mucin-degrading bacteria inhabiting the gastrointestinal tract associated with host phenotypes and disease states.

OBJECTIVE

Explore characteristics of overweight and obese female early-stage (0 to II) breast cancer patients with low AM relative abundance (LAM) vs high (HAM) enrolled in a presurgical weight-loss trial.

DESIGN

Secondary analysis of pooled participants in a randomized controlled trial (NCT02224807).

PARTICIPANTS/SETTING: During the period from 2014 to 2017, 32 female patients with breast cancer were randomized to weight-loss or attention-control arms from time of diagnosis-to-lumpectomy (mean=30±9 days).

INTERVENTION

All were instructed to correct nutrient deficiencies via food sources and on upper-body exercises. The weight-loss group received additional guidance to promote 0.5 to 1 kg/wk weight-loss via energy restriction and aerobic exercise.

MAIN OUTCOME MEASURES

At baseline and follow-up, sera, fecal samples, two-24 hour dietary recalls and dual x-ray absorptiometry were obtained. Bacterial DNA was isolated from feces and polymerase chain reaction (16S) amplified. Inflammatory cytokines were measured in sera.

STATISTICAL ANALYSES PERFORMED

Differences between LAM and HAM participants were analyzed using t tests and nonparametric tests. Spearman correlations explored relationships between continuous variables.

RESULTS

Participants were aged 61±9 years with body mass index 34.8±6. Mean AM relative abundance was 0.02% (0.007% to 0.06%) and 1.59% (0.59% to 13.57%) for LAM and HAM participants, respectively. At baseline, women with HAM vs LAM had lower fat mass (38.9±11.2 kg vs 46.4±9.0 kg; P=0.044). Alpha diversity (ie, species richness) was higher in women with HAM (360.8±84.8 vs 282.4±69.6; P=0.008) at baseline, but attenuated after weight-loss (P=0.058). At baseline, interleukin-6 level was associated with species richness (ρ=-0.471, P=0.008) and fat mass (ρ=0.529, P=0.002), but not AM. Change in total dietary fiber was positively associated with AM in LAM (ρ=0.626, P=0.002), but not HAM (ρ=0.436, P=0.180) participants.

CONCLUSIONS

Among women with early-stage breast cancer, body composition is associated with AM, microbiota diversity, and interleukin-6 level. AM may mediate the effects of dietary fiber in improving microbiota composition.